Thaddaeus sits next to 4 phonetic neighbors — Theodore, Tobias, and Matthias are the closest matches by sound. Most share Thaddaeus's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"heart, courageous heart"
"Yahweh saves"
"hand of God"
"the ringed planet, sixth from the sun"
"little slender one"
"victory of the people"
"short; courtly"
"wolf shield"
"lord, master"
"one who is celebrated"
"from the winding stream or lane"
"son of Jeffrey, son of peace"
"comparable to God, God-like"
"desired, longed for"
"God strengthens"
"of the Lord"
"first among thinkers"
"one who does not speak, baby"
"son of Brayden"
"of the sun, relating to the sun"
Similar sound: These names share phonetic patterns with Thaddaeus — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Aramaic origins, giving them the same cultural heritage as Thaddaeus.
Rhythm: Thaddaeus is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.